The present invention relates to an apparatus and a method for judging content data by embedding an electronic watermark in data such as image data or audio data prepared by a digital device, and subsequently detecting the embedded electronic watermark. In particular, the present invention pertains to a content data judging apparatus and a method for maintaining security, by performing an appropriate authentication process, involving the use of a digital device, a recording medium and a plurality of programs, and by inspecting content data for alterations and identifying portions containing altered data. The present invention also pertains to an insurance service processing system using the apparatus and the method.
A conventional, well known method for detecting the alteration of image data uses a hash function to prepare in advance information that is added to image data. This information is compared with a hash value produced based on the image data to determine whether the image data were altered. But while the alteration of image data can be detected using this method, a data portion containing altered image data can not be identified. To resolve this problem, the invention in Japanese Patent Application No. Hei 11-158358 was submitted. In this invention, a method is described whereby additional information for detecting an alteration is embedded in content data as an electronic watermark, and the content data portion containing altered data is identified by detecting the additional information.
However, this method does not provide a system for judging content data. A judging operation comprises functions for accurately determining whether an exchange of content data occurred from the time the data were produced until an alteration of the data was detected, for identifying an occasion on which the content data may be altered, and for identifying a portion of the data that was altered.
In addition, the conventional method does not provide a system for maintaining security in order to handle, as evidence, content data prepared by a digital device, such as a camera, a recording device, a scanner or a video camera, or a process for a claim service and an insurance service that uses the data.
Furthermore, the conventional method does not provide a mechanism for determining whether identification data were altered, and for, if the data were altered, identifying a portion containing altered data.
Further, the conventional method does not provide a standardized content data judging method and apparatus, regardless of the digital device type that prepares content data.
To resolve the above problems, it is one object of the present invention to provide a content data judging apparatus and method for accurately determining whether an exchange of content data occurred from the time the data were produced until an alteration of the data was detected, for identifying an occasion on which the content data may be altered, and for identifying a portion of the data that was altered.
It is another object of the present invention to provide a method and a system for maintaining security for accurately determining whether an exchange of content data, or a process for a claim service and an insurance service which uses these content data.
It is an additional object of the present invention to provide a method and a system for determining whether identification data was altered and for identifying a portion of data that was altered.
Content Data Judging Apparatus
A content data judging apparatus, which determines whether content data prepared by a digital device were altered, comprises: (1) means for performing an authentication process using a medium on which content data are recorded; (2) means for reading the content data from the medium; (3) means for embedding, in the content data, data for verifying the pertinent contents; (4) means for extracting, from the content data, the data for verifying the pertinent contents; and (5) means for using the results of the extraction to determine whether the content data were altered. Preferably, the means (5) includes means for, when the content data were altered, identifying a portion containing altered data.
Preferably, the content data recorded in the medium includes the results of an authentication process performed for the digital device and the medium, and the means (2) for reading the content data includes means for reading the results of the authentication process.
Preferably, the means (3) for embedding data for verifying the content data includes means for embedding, in the content data, authentication history information for content data and ID information, such as a creation date, a creator, a creating device and a registration date.
Apparatus for Embedding Data Used for Alteration Detection
An apparatus, for embedding alteration detection data in content data prepared by a digital device, comprises: (1) means for performing an authentication process using a medium on which content data are recorded; (2) means for reading content data stored on the medium; and (3) means for embedding, in the content data, alteration detection data used to identify a portion containing altered data and for storing the resultant content data.
Content Data Alteration Judging Apparatus
A content data alteration judging apparatus comprises: (1) means for extracting alteration detection data from content data; and (2) means for using the results of an extraction of the alteration detection data to determine whether the content data were altered, and for, when the content data were altered, identifying a portion containing altered data.
Image Data Judging Apparatus
An image data judging apparatus, which includes a digital camera, a recording medium on which an image acquired by a digital camera is recorded, an electronic watermark embedding device for accessing and reading image data stored on the recording medium and for embedding an electronic watermark in the image data, and an electronic watermark extraction device for extracting the electronic watermark from the image data, comprises: (1) means for preparing image data in the digital camera; (2) means for performing an authentication process between the digital camera and the recording medium; (3) means for, when the authentication process is successful, recording the image data on the recording medium; (4) means for performing an authentication process between the recording medium and the electronic watermark embedding device; (5) means for, when the authentication process is successful, using the electronic watermark embedding device to read the image data from the recording medium; (6) means for using an electronic watermark embedding device to embed in the image data, as an electronic watermark, alteration determination data, as well as the results obtained by the several authentication processes and ID information for the image data; (7) means for using the electronic watermark embedding device to record, on a storage device, the image data in which the electronic watermark was embedded; (8) means for using the electronic watermark detection device to read the image data from the storage device and to extract the electronic watermark from the image data; and (9) means for using the electronic watermark detection device to determine whether the image data were altered, and for identifying a portion containing altered image data.
Image Data Judging Method
A method for judging an image acquired by a digital camera comprises the steps of: (1) preparing image data in digital camera; (2) performing an authentication process between the digital camera and a recording medium; (3) recording the image data on the recording medium when the authentication process is successful; (4) performing an authentication process between the recording medium and a device driver; (5) performing, when the authentication process is successful, an authentication process between the device driver and an electronic watermark embedding program; (6) permitting the electronic watermark embedding program to read the image data from the recording medium; (7) permitting the electronic watermark embedding program to embed in the image data, as an electronic watermark, alteration determination data, as well as the results of the several authentications processes and ID information for the image data; (8) permitting the electronic watermark embedding program to record on a storage device the image data in which the electronic watermark was embedded; (9) permitting an electronic watermark detection program to read the image data from the storage device and to extract the electronic watermark from the image data; and (10) permitting the electronic watermark detection program to use the extracted electronic watermark to determine whether the image data were altered, and to identify a portion containing altered image data.
Insurance Service Processing System
An insurance service processing system, which detects the alteration or the substitution of evidence data in order to safely and efficiently perform a service process for the assessment of damages, comprises: (1) means for using a digital device to prepare evidence data for an object; (2) means for embedding alteration detection data in the evidence data and for recording the resultant evidence data on a storage device; (3) means for the extraction of the alteration detection data from the evidence data, for using the results of the extraction to determine whether the evidence data were altered, and for, when the evidence data were altered, identifying a portion containing altered data and judging the evidence data recorded on the storage device.
Insurance Service Processing Method
An insurance service processing method, for detecting the alteration or the substitution of evidence data in order to safely and efficiently perform a service process for the assessment of damages, comprises the steps of: (1) using a digital device to prepare evidence data for a damaged object; (2) embedding alteration detection data in the evidence data, and recording the resultant evidence data on a storage device; (3) performing an extraction of the alteration detection data from the evidence data, using the results of the extraction to determine whether the evidence data were altered, and, when the evidence data were altered, identifying a portion containing altered data and judging the evidence data recorded on the storage device.
Smart Card
A smart card used for identifying an owner comprises: (1) a card face on which the name of the owner or a card number is written; and (2) a storage device on which is recorded, for the owner, evidence data in which alteration detection data was embedded to identify a portion containing altered data.
Evidence Data Detection Apparatus
An evidence data detection apparatus, which includes a smart card reader for reading data from a smart card, comprises: (1) means for reading, from the smart card, evidence data for an owner in which alteration detection data were embedded; and (2) means for using the results of an extraction of the alteration detection data to determine whether the alteration detection data were altered, and for, if the alteration detection data were altered, identifying a portion containing altered data.
Medium Including a Program for Embedding Alteration Detection Data
A medium is provided which includes a program for embedding alteration detection data in content data prepared by a digital device, the program permitting a computer to perform: (1) a function for performing an authentication process for a recording medium on which content data are recorded; (2) a function for reading the content data from the recording medium; and (3) a function for embedding, in the content data, alteration detection data for identifying a portion containing altered data, and for recording the resultant content data on a storage device.
Medium Including a Program for Determining Whether Content Data Were Altered
A medium is provided which includes a program for determining whether content data were altered, the program permitting a computer to perform: (1) a function for extracting alteration detection data from content data; and (2) a function for using the results of an extraction to determine whether the content data were altered, and for, when the content data were altered, identifying a portion containing altered data.
Preferably, the digital device is a camera, a recording device, a scanner or a video camera. In the following description of an alteration determination apparatus, a detailed explanation will be given for the means for embedding alteration detection data in the content data, the means for extracting the alteration detection data from the content data, and the means for using the results of an extraction to determine whether the content data were altered; and for, when the content data were altered, identifying a portion containing altered content data.
Alteration Determination Apparatus
According to the present invention, a content alteration determination apparatus comprises: alteration detection data embedding means (hereinafter referred to as a data addition device) for adding predetermined embedded data to content data; and a determination device for determining whether the content data were altered. The data addition device includes: content data division means for dividing at least one part of the content data to obtain first blocks; and embedded data addition means for adding predetermined first embedded data to each of the first blocks to obtain second blocks. The determination device includes data extraction means (alteration detection data extraction means) for extracting the embedded data (second embedded data) added to at least one part of each second block, and alteration determination means (altered portion identifying means) for using the extracted second embedded data to determine whether at least one part of each second block was altered.
Preferably, an alteration determination apparatus includes a data addition device for adding to image data predetermined embedded data and a determination device for determining whether the image data were altered. The data addition device includes image division means for dividing image data to obtain first image blocks, and embedded data addition means for adding predetermined first embedded data to each of the first image blocks to obtain second blocks. The determination device includes embedded data extraction means for extracting embedded data (second embedded data) added to each of the second image blocks, and alteration determination means for using the second embedded data to determine whether each of the second image blocks was altered.
Preferably, the image division means divides the image data to obtain first image blocks, each of which includes a number of data units. The embedded data addition means makes an adjustment so that the first embedded data are represented, in accordance with a predetermined rule, by the relationship of the corresponding data unit values that are included in the two or more first image blocks that correspond to each other, and adds the first embedded data to each of the first image blocks to obtain the second image blocks.
Preferably, when one of the second image blocks is altered, the embedded data addition means makes an adjustment so that the data unit values that are included in the pertinent second image blocks and that correspond to each other do not follow the predetermined rule.
Preferably, the embedded data extraction means extracts, from each of the second image blocks, the second embedded data that is represented, in accordance with the predetermined rule, by the relationship of the data unit values included in the individual second image blocks.
Preferably, the alteration determination means uses the results of a comparison of the first embedded data with the extracted second embedded data to determine whether any of the second image blocks were altered.
Preferably, the first and the second image blocks are conversion blocks, each of which includes data units and at least one pair of conversion coefficients obtained by dividing image data to obtain predetermined process blocks, and by transforming the blocks from spatial areas to frequency areas.
Preferably, the first and the second image blocks are DCT blocks, each of which includes data units and one pair of DCT coefficients obtained by dividing image data into predetermined DCT blocks and by performing a discrete cosine transformation (DCT) for the blocks.
Processing by Alteration Determination Apparatus
According to the present invention, the alteration determination apparatus first divides content data into a plurality of portions.
The content data can be, for example, image data for audio data or for damaged vehicles and objects at a traffic accident. If such content data are altered intentionally, they can not be used as evidence data.
Next, the alteration determination apparatus embeds data (a so-called electronic watermark (digital watermark)) in each portion of the resultant content data. The embedded data are used to determine whether an alteration has occurred, and are embedded using a predetermined method whereby the embedding of data in another portion is not affected, and whereby the detection of an alteration has no affect on another portion. That is, a closed form is used for embedding data in each of the portions of the content data. Finally, the alteration detection apparatus performs a closed process to detect data in the portions of the data contents, and determines whether the data were altered.
Specific Examples Used in the Following Explanation
Any method for embedding an electronic watermark (embedded data) in divided image data portions may be used, just so long as the alteration determination apparatus of this invention can embed an electronic watermark having a closed form in each separate portion of image data.
As a specific example for the explanation, the alteration determination apparatus of the invention divides image data encoded using the JPEG method into a plurality of sets (image blocks), each of which includes a plurality of DCT coefficients; embeds an electronic watermark in each set in order to determine whether an alteration has occurred; and for each set determines whether image data were altered.
The alteration determination apparatus of the invention may embed data (an electronic watermark) in one part of image data to detect an alteration, or may not match a data embedded area with an alteration detection area. In the following explanation, as another specific example, the alteration determination apparatus embeds data in all of the image data and determines whether an alteration has occurred.
As an additional example, the DCT coefficients used by the alteration determination apparatus to embed data (an electronic watermark) are obtained, for example, by forming luminous elements (Y) of color image data into a plurality of 8xc3x978 pixel DCT blocks (macro blocks), and by performing a DCT process for the DCT blocks.
As a further example, a method used to select a set including a plurality of DCT coefficient pairs is, for example, a method used to select a set of DCT coefficients by using a random number, or a method used to select as a set adjacent DCT coefficients. Hereinafter, DCT coefficient pairs are obtained using the second method, i.e., a DCT coefficient set is an adjacent DCT coefficient pair that is obtained by a DCT transformation of two adjacent DCT blocks.
Processing Using a Data Addition Device
In the alteration determination apparatus of the invention, the data addition device embeds data (an electronic watermark) in image data in order to determine, for each pair of DCT coefficients, whether an alteration has occurred.
Image Division Means
In the data addition device, the image division means performs Huffmann decoding of image data compressed using the JPEG method. Then, of three image data elements obtained as a result, the image division means accepts a DCT coefficient of the luminance element (Y), and correlates it with an adjacent DCT coefficient to form a pair (first image block) of the adjacent correlated DCT coefficients.
Embedded Data Addition Means
The embedded data addition means extracts at least one (one data unit) of the two DCT coefficients included in each pair (first image block) in correlation with each other (since at least one of the two DCT coefficients is extracted, a plurality of data units are selected from one pair).
Further, the embedded data addition means uses key information to generate a random number, and uses the random number to perform a scramble process for 96 bits of embedded data.
The embedded data addition means correlates the pair (first image block) with each bit of the scrambled embedded data (first embedded data).
The embedded data addition means extracts one of the two DCT coefficients in a pair (first image block). To embed data, the embedded data addition means adjusts the DCT coefficient values (data unit values) correlated with each other, so that the relationship of these DCT coefficients represents the value (1 or 0) of the data bit (first embedded data) that corresponds to the pair (first image block) that includes the DCT coefficients in accordance with the predetermined rule.
The method used for selecting DCT coefficients from the two DCT coefficients included in a pair (first image block) may be a method for the selection of DCT coefficients in accordance with a fixed correlation, or a method for the selection of DCT correlated coefficients based on a random number.
As a specific example, for each pair (a first image block) in the following explanation, a random number is used to select three corresponding DCT coefficients (a total of six) from two DCT blocks in a pair, i.e., when a pair differs, DCT coefficients are selected from different locations, while when the same pair is used, DCT coefficients are selected at the same location.
When data bits are embedded in each pair, the alteration of a specific pair does not affect the other pair, unlike when data are embedded using a hash function. That is, when data are embedded in the above described manner, the alteration of one image data portion does not affect the other image data portions, and thus, whether image data was altered can be determined for each portion.
Processing Performed by Determination Device
When bites of data (first embedded data) are embedded, and when image data are altered by pasting in one part of image data and by erasing a photo image, the relationship of DCT coefficients (data units) that are included in a pair (second image block) in the altered portion and correlate with each other does not follow the above predetermined rule. Thus, the bit value of the embedded data (second embedded data) differs from the bit value of the first embedded data.
When the first 96 bits of embedded data, for example, are embedded in 6144 pairs (first image block) of DCT coefficients that constitute an image of 1024xc3x97768 bits, each bit of the first embedded data is embedded in 64 sets of image data.
When only a comparatively small portion of image data is altered, the number of pairs for the altered portion that do not represent the bits of corresponding embedded data (the first embedded data) should be smaller than the number of pairs that represent the bits of the corresponding embedded data (the first embedded data).
Therefore, when the second embedded data are extracted from an image that may be altered, and a majority bit decision is used to decide, in accordance with the predetermined rule, whether the value represented by each pair of the 64 extracted data pairs (the second image blocks), which correspond to the same bit in the first embedded data, is a 1 or is a 0, the value represented by the majority of pairs is determined to be the value of the embedded data (the first embedded data) added by the data addition device.
Similarly, as a result of the majority bit decision, it can be assumed that at the locations of the minority of the pairs (the second image blocks) altered data were added.
A property of embedded data is used by the determination device of the present invention. That is, the determination device extracts, from DCT coefficient pairs (second embedded data) that may be altered, data (second embedded data) that may, as the result of an alteration, have values that differ from their original values.
In addition, the determination device uses the extraction results to determine which DCT coefficient pair (second image block) was altered, i.e., what portion of image data was altered.
Embedded Data Extraction Means
In accordance with the predetermined rule, the embedded data extraction means extracts a value (second embedded data), represented by corresponding DCT coefficients (data units), that is included in two DCT coefficients in a pair (a second image block) that may be altered after the first embedded data were added by the data addition device.
Alteration Determination Means
The alteration determination means uses the majority bit decision to decide whether the value represented by the majority of pairs (second image blocks) corresponding to the same bit of the embedded data is a 1 or is a 0, and determines that pairs having that majority value are first embedded data. Furthermore, the alteration determination means determines that a pair (a second image block) that represents a value different from that of the first embedded data was altered.
Data Addition Device
The data addition device of the present invention adds predetermined embedded data to image data in order to determine whether the image data were altered. For this determination, the second embedded data, which are added to a plurality of second image blocks included in the image data, are used to determine whether each of the second image blocks was altered. The data addition device includes image division means for dividing image data to obtain a plurality of first image blocks, and embedded data addition means for adding predetermined first embedded data to each of the thus obtained first image blocks to form a plurality of second image blocks.
Determination Device
The determination device of the present invention divides image data to obtain a plurality of first image blocks, and adds predetermined first embedded data to each of the thus obtained first image blocks to form a plurality of second image blocks. The determination device then ascertains whether each of the second image blocks was altered. Included in the determination device are embedded data extraction means, for extracting second embedded data that were added to each of the second image blocks, and alteration determination means, for using the extracted second embedded data to determine whether each of the second image blocks was altered.
Alteration Determination Method
According to the alteration determination method of the present invention, predetermined embedded data are added to object content data, and whether the resultant content data were altered is determined. The alteration determination method comprises the steps of: dividing the content data to obtain a plurality of first blocks; adding predetermined first embedded data to the individual first blocks to form a plurality of second blocks; extracting the second embedded data from the second blocks; and using the second embedded data to determine whether each of the second blocks was altered.
Recording Medium
A first recording medium according to the present invention is provided for an alteration determination apparatus that includes a data addition device, for adding predetermined embedded data to image data, and a determination device, for determining whether such image data are altered. The first recording medium is used to record a program that permits a computer to perform: an image division step of dividing image data to obtain a plurality of first image blocks; an embedded data addition step of adding predetermined first embedded data to the individual first image blocks to form a plurality of second image blocks; an embedded data extraction step of extracting the embedded data (second embedded data) from each of the second image blocks; and an alteration determination step of using the obtained second embedded data to determine whether each of the second image blocks was altered.
According to the present invention, a second recording medium is provided for a data addition device that adds predetermined embedded data to image data in order to determine whether the image data were altered. For this determination, the second embedded data which are added to each of the second image blocks included in the image data, are used to determine whether the second image blocks were altered. The second recording medium is used to record a program that permits a computer to perform: an image division step for dividing image data to obtain a plurality of first image blocks; and an embedded data addition step for adding predetermined first embedded data to the individual first image blocks to form a plurality of second image blocks.
According to the present invention, a third recording medium is provided for a determination device that divides image data to obtain a plurality of first image blocks, that adds predetermined first embedded data to the individual first image blocks to form a plurality of second image blocks, and that determines whether each of the second image blocks was altered. The third recording medium is used to record a program that permits a computer to perform: an embedded data extraction step of extracting embedded data (second embedded data) from the second image blocks; and an alteration determination step of using the extracted second embedded data to determine whether each of the second image blocks was altered.